The present invention relates generally to electronic devices, and more specifically, to driving the common-mode of a Josephson parametric converter using a short-circuited coplanar stripline.
A Josephson ring modulator (JRM) is a nonlinear dispersive element based on Josephson tunnel junctions that can perform three-wave mixing of microwave signals at the quantum limit. The JRM consists of Josephson Junctions (JJs). In order to construct a non-degenerate parametric device, namely the Josephson parametric converter (JPC), which is capable of amplifying and/or mixing microwave signals at the quantum limit, the JRM is coupled to two different microwave resonators.
In microstrip JPCs, as well as compact and shunted JPCs, the pump drive that provides the energy for the amplification process is fed through the sum port (Σ) of a 180 degree hybrid coupler. The difference port (Δ) of the same hybrid coupler is used to feed the signal or idler tones to the JPC. In this configuration, both the pump and the signal or idler are fed to the JPC through the same feedlines and coupling capacitors of the JPC. The 180 degree hybrid coupler is connected to these feedlines.